org.eclipse.core.internal.preferences

Class ImmutableMap

java.lang.Object

org.eclipse.core.internal.preferences.ImmutableMap

All Implemented Interfaces:

java.lang.Cloneable

public abstract class ImmutableMap
extends java.lang.Object
implements java.lang.Cloneable

Hash table of {String --> String}. This map handles collisions using linear probing. When elements are removed, the entire table is rehashed. Thus this map has good space characteristics, good insertion and iteration performance, but slower removal performance than a HashMap.

This map is thread safe because it is immutable. All methods that modify the map create and return a new map, rather than modifying the receiver.

Field Summary

Fields

Modifier and Type	Field and Description
static ImmutableMap	EMPTY The empty hash map.
protected static java.lang.String[]	EMPTY_STRING_ARRAY

Constructor Summary

Constructors

Constructor and Description
ImmutableMap()

Method Summary

Modifier and Type	Method and Description
protected static ImmutableMap	createMap(int i)
abstract java.lang.String	get(java.lang.String key) Returns the value associated with this key in the map, or null if the key is not present in the map.
protected abstract void	internalPut(java.lang.String key, java.lang.String value) Destructively adds a key/value pair to this map.
abstract java.lang.String[]	keys() Returns an array of all keys in this map.
abstract ImmutableMap	put(java.lang.String key, java.lang.String value) Returns a new map that is equal to this one, except with the given key/value pair added.
abstract ImmutableMap	removeKey(java.lang.String key) Returns a map that is equal to this one, except without the given key.
void	shareStrings(StringPool set)
abstract int	size() Returns the number of keys in this map.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY

public static final ImmutableMap EMPTY

The empty hash map. Since instances are immutable, the empty map can be a singleton, with accessor methods optimized for the empty map case.

EMPTY_STRING_ARRAY

protected static final java.lang.String[] EMPTY_STRING_ARRAY

Constructor Detail

ImmutableMap

public ImmutableMap()

Method Detail

get

public abstract java.lang.String get(java.lang.String key)

Returns the value associated with this key in the map, or null if the key is not present in the map.

Parameters:

key -

Returns:

The value associated with this key, or null

createMap

protected static ImmutableMap createMap(int i)

internalPut

protected abstract void internalPut(java.lang.String key,
                                    java.lang.String value)

Destructively adds a key/value pair to this map. The caller must ensure there is enough room in this map to proceed.

Parameters:

key -

value -

keys

public abstract java.lang.String[] keys()

Returns an array of all keys in this map.

put

public abstract ImmutableMap put(java.lang.String key,
                                 java.lang.String value)

Returns a new map that is equal to this one, except with the given key/value pair added.

Parameters:

key -

value -

Returns:

The map containing the given key/value pair

removeKey

public abstract ImmutableMap removeKey(java.lang.String key)

Returns a map that is equal to this one, except without the given key.

Parameters:

key -

Returns:

A map with the given key removed

shareStrings

public void shareStrings(StringPool set)

size

public abstract int size()

Returns the number of keys in this map.

Returns:

the number of keys in this map.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object